Amplifier tube



Jan. 6, 1931.

s. LCEWE AMPLIFIER TUBE Filed Oct. 20. 1926 INVENTOR SIEGMUND LOEWE BY I jaafzadm TORNEY Patented Jan. 6, 1931 j UNirEn starts SIEGMUND LOEWE, OEBERLIN, FBIEDENAU, onnivrniw, asssnonaro 'amo CORPRA o e onor AMERICA, A conronaron on DELAWARE AMPLIFIEB TUBE Application filed October 20, 1926, Serial No. 142318, and in Germany October 21, 1925.

This invention relates to a vvacuum tube and' more particularly to a single vacuum tube for producing multi-stage amplification of low 'requency Currents. e

The use of a high resstan'ce in the'plate circuit of an amplifier to produce a very high and e'icient potential `arnpliication is well` known. However, the Value of the res-istance used is limited by straycapacities, such as m exist between the leads and internal elements of the tubes, where there is more than one stage of amplification, and in turn, this limits- ;the potential amplification.

It is an object of this invention to reduce 1 such stray capacities to a minimum. This, as will be pointed outlater in greater detail,

is accomplished by placing the elements of the various stages withina single Vacuous space thereby reducing the length of the leads.

Another object of this invention is to build an ineXpensive multistage low frequency amplifier.

A further object is to build a multi-stage anplication unit, that is compact; and can 93 be used effectv'ely in various circuits to simplify them. r

Other objects as well as advantages will appear. as the description ofthe invention 'proceeds.` i

::e In the accompanying drawing I have shown an embodiment of my nvention, namely, a two stage resistance coupled amplifier within asingle tube; The glassbulb of the tube is indicated at 12. v y y si It is to be understood of course that amplification systems other than those shown may be used. i

In the drawing 1 designates a compressed foot or base through which run the leads to 40 the anplificationsystems 7 designatesthe elements' of the firststag'e of amplification i and those of the second; As is clearly shown the filaments of the two stages are ,connected inseries, the external leads %and 3 rovidin a means whereb i a heatim current e may be supplied to them. 4 is the lead to the first grid,'5 to the first plate and 6 to the second plate. 9 indicatesa high resistance used in the plate circuit of the first stage fol' the purpose of producing high potential' amintricate wiring;

plification. ll is the well known grid conwithin an eXhausted tube. Resistance 10 is the well known grid leak resistance. Re: sistances9 and 10 should be of the type that will not undergo achange in value dueto heating such as the heating ofthe tube when the vacuum within it is being produced. Resistances of this kind may be obtained by vaporzing 'carbon or rnetal upon 'a' glass or quartz carrier. v i

The resistances 9 and lO are not disposed in' the plane of the two systems"? and S as illustrated, but one resistance, for example, 9 is placed behindthe plane of the drawing and the other in front of that plane. ,This is done in order to reduce Capacity effects to a minimumand also to reduce the total space once apparent By placingthe elements ofeach amplification 'system as well as the coupling means within a single tube the need for separate tubes as well as complicated connections is dispensed with. By quantity productionof these tubes a unitary inulti-stage amplification system 'can be produced which u is 'less expensive than the cost of several sin gle 'stage units, which would be required to produce theisame amplification. p "By mounting the' elements and coupling means on a single base this amplication device becomes easy to handle. It is clear that the'use of such' a device in various cir'cu'its will simpli-fy'them and avoid thenecessity of Having described my invention what I claimis: e v

` In a multi-stage vacuum tube, a base; a plu- 'ality of amplifier units, each comprising a e ;1

control electrode, a cthode and an anode mounted in one plane en said base; a, cou pling condenser connectng the anode of one of said unts with the grd of another; a resstanceconnected to one side of said condenser; and another resstance connected .to the other side of said eondenser; said resist- }ances being mounted 'in a plane traversng the plane of said units. i

' SIEGMUNDLOEWE, 

